Add active/inactive/game-time timers to fleet + server pages

Fleet cards and the per-server detail hero now show three live-ticking
timers: Active (since players > 0), Inactive (since server emptied), and
Game (since InitGame in games_sp.log, back-computed from the log's own
MM:SS prefix so it stays accurate across restarts). Anchors are
persisted on `servers` and fanned out via the SSE bus; a single 1s
ticker feeds every card. Idle map cycles are filtered out so the game
timer doesn't flicker.

src/lib/server/fleet/servers.ts

@@ -84,6 +84,10 @@ export interface ServerRow {
     image: string | null;
     created_by: string | null;
     destroyed_at: string | null;
+    active_since: string | null;
+    inactive_since: string | null;
+    game_started_at: string | null;
+    game_ended_at: string | null;
     created_at: string;
 }
 
@@ -169,7 +173,11 @@ export function setServerField(
         'game_id',
         'image',
         'created_by',
-        'destroyed_at'
+        'destroyed_at',
+        'active_since',
+        'inactive_since',
+        'game_started_at',
+        'game_ended_at'
     ];
     if (!allowed.includes(field)) throw new Error(`refusing to set ${field}`);
     db().prepare(`UPDATE servers SET ${field} = ? WHERE name = ?`).run(value, name);